2000 Chrysler 300 Oil Burner

It sounds like you have blown a head gasket. The overheating may have caused the problem. However, the white smoke from the exhaust is the dead give away. Coolant burns white when it enters a combustion chamber. To confirm, check the motor oil to see if there is any coolant mixed with the oil. You mentioned the coolant appeared to have oil in it which is possible too. WHen the engine is cold, open the radiator and see if there is any pressure pushing the coolant out. Finally, if all else looks good, you will need to perform a compression test. Here is a how to for checking it. You will need a compression gauge. Most parts stores will lend or rent them.

https://www.2carpros.com/dia/how_to_check_compression.htm

Let me know what you find or if you have other questions, and thanks for using 2carpros.com.

Joe